1. Field of the Invention
This invention is in the field of automated systems that clean the walls of tanks.
2. Why this Invention is Needed
Preparing and maintaining artificial aquatic habitats where different kinds of plants and animals live is an engrossing pastime that is enjoyed by large numbers of people in many countries. Those artificial habitats are established in a tank with one or more transparent walls that are made of either glass or acrylic plastic. The aim is to give people the pleasure of observing the growth, movements and interactions of freshwater or marine animal species that often live amongst a variety of plant life that contributes to an approximation of a natural ecosystem.
The maintenance of such an aquatic habitat, whether it is large or small, is time-consuming. One of the obvious tasks is to keep the transparent walls of the tank clear of any algae or other growth that, if not controlled, will soon block the observer's view, thereby defeating the purpose of such a project. It will be especially difficult to keep such growth under control if the aquarium owner is absent for an extended period of time, leading to neglect of what must be a regularly scheduled cleaning process. What is needed, therefore, is a practical, fully automated system that will keep the tank's walls clean. To be widely accepted, it must be easy to install on different tank designs that are in common use. It must be easy to set up and configure, flexible in its operation, safe to use and reliable, and resistant to damage. As well, to gain acceptance it must be affordable for a significant number of aquatic habitat enthusiasts. The goal of the present invention is to fully respond to those needs.
3. Prior Art and its Limitations
Manually-Operated, Magnetically-Coupled Brushes
Many different kinds of cleaning implements, a few with motorized brushes or scrapers, have been developed to enable the person maintaining the aquarium to manually remove algal growth from the walls. Among them are magnetically-coupled, “inside-outside” paired elements that enable the user to move the outside element along the outer surface of an aquarium wall to cause a corresponding movement of the coupled cleaning device along the inner surface on the adjacent side of the wall, thereby removing the algal growth. By using such a magnetically-coupled device, the person who is doing the cleaning avoids having to introduce a cleaning device with a long handle into the aquarium where it may easily disturb the plant and animal life. Moreover, it is much easier to observe the efficacy of the cleaning action when those doing the work can readily observe the effect of their efforts. Although with proper effort such devices can do the job well, not everyone has the time and patience to do this work as regularly as is required to allow for the uninterrupted pleasure of viewing the aquatic life through transparent walls.
A few examples of the prior art in the field of manually-controlled devices of that kind are: U.S. Pat. No. 6,634,052 issued on Oct. 21, 2003 to Hanson that features interchangeable cleaning elements. Some devices, such as U.S. Pat Application US 2010/0083983 to Linden, teach ways to choose between two kinds of cleaning element on the inner element while the two elements are coupled, by having the user act upon a control element on the outer element.
Some manually-operated cleaning devices are adapted to allow the inner element to be transferred from one tank wall to another when the outer element is moved to the second wall. An example is U.S. Pat. No. 6,206,978 issued on Mar. 27, 2001 to Tsui. That design is designed for use in tanks that have rounded corners, such as some models of tanks with acrylic walls. Another example of prior art designed for this purpose is U.S. Pat. No. 7,506,612 issued to Enoch et al. on Mar. 24, 2009.
Limitations of Previous Attempts to Develop an Automated Cleaning System for Tanks
Rafailovich, in U.S. Patent Application 20060174840, proposed a system with magnetically-coupled inner and outer elements wherein a drive system is integrated into the outside element. One significant limitation of this system is its inability to automatically move from one wall of the aquarium to another. A comparable system in terms of its operating principles, one of several that have been designed to clean windows in buildings, is described in Int. Application PCT/EP2000/005870 filed by Schlosser. Prior art designs related to window-cleaning, however, do not have to transfer such devices around a corner from one surface to another, which is a necessary feature for a system that will be used in tanks with multiple viewing surfaces.
A system proposed by Schneider in German Pat. Application DE 10 2008 027 describes a system designed to clean the inner surface of a tank that has a single wall of cylindrical curvature, with that cylinder having a vertical axis. Such tanks may include large aquarium visited by the public. Schneider's design shows a horizontal rail that extends three-quarters of the way around the tank. A moving cleaning element travels back and forth along that rail. The rail must be very substantial in construction, as it is only supported at its ends. The rail is raised and lowered to enable the moving element to clean different long, narrow horizontal swaths of wall surface. The cleaning method taught by Schneider is not adapted for use in a tank that has walls that meet at a corner. Moreover, in order to create a discontinuous cleaning path that would avoid obstacles at certain points, the large rail would have to be moved up and down making such a maneuver slow, and requiring a powerful drive system.
U.S. Pat. No. 5,806,463 issued to Rising on Sep. 15, 1998 teaches a specially modified aquarium that includes a cleaning system that is best adapted to clean his “aquarium tank that is particularly enclosed in a wall recess such that there is a single viewing surface”. Rising's design does not use magnetically-coupled elements, as all elements of the system are located within the tank. This design only provides for horizontal movement of the full-height cleaning element. Rising explains that his invention can only properly clean a tank with multiple viewing surfaces if the tank corners are significantly rounded. However, the simplistic figure that shows how his system would go around a corner contradicts his more detailed drawings. Those figures teach a system that can only be used on a single viewing surface. Rising proposes that areas in a “square tank” that cannot be cleaned—areas near the corners—should be concealed by “side corner moldings”. We will discuss below additional limitations of this design in comparison with our invention, in the section of this application entitled “Specific competitive advantages of this invention”.
Summary of the Need for Improved Technology
An examination of the prior art therefore reveals a need for an unattended, automated cleaning system that can easily be retrofitted to existing aquariums. Such a system should be able to clean the inner surfaces of the walls of tanks which have with either curved walls or planar walls, with those walls meeting at rounded or angular corners, with the entire wall being thoroughly cleaned, including areas adjacent to the corners. There is a further need for such a tank cleaning system to be able to avoid obstacles such as snails that may attach themselves to the walls. The mechanical components of the system should be outside the tank to avoid water, or the attachment of life forms and the growth of algae on the components, and possible contamination of the tank contents. Given the many differences that exist between one aquatic habitat and another, there is a need for a system that provides for cleaning operations that can be easily specified by the user, in terms of cleaning pattern and schedule, to adapt the system to the user's specific needs.
Objects and Advantages
The present invention answers the need for a practical and effective, fully automated aquarium wall cleaning system that overcomes the limitations of previous designs. The objects of this invention therefore include that the system:                a) can be sold as an after-market kit that can be fitted to a large proportion of the aquarium designs that are now in use;        b) can, in one continuous process, automatically clean both surfaces of the four walls of the most common kind of aquarium, with the quality of the work done being high enough to satisfy the most demanding consumer;        c) can move the cleaning element that is applied to the surface of the inner wall in any direction, including horizontal sweeps, vertical sweeps, diagonal sweeps, or even curved sweeps, and in repeated fashion, thereby ensuring thorough cleaning of the most difficult areas;        d) can be programmed, under microprocessor control, to do the required cleaning at the preferred time of day and at the preferred frequency of cleanings per week. It can also be programmed to clean specific areas more thoroughly or more often—areas where lighting conditions or sand promote more vigorous algal growth;        e) can be programmed to move around fixed obstacles such as filtration systems that are inside the aquarium adjacent to a wall;        f) can detect and avoid obstacles such as snails that will be constantly changing their positions on the inner surfaces of the aquarium walls; and        g) will provide for safe operation by incorporating sensors that enable the control system to shut the system down if something interferes with system's normal operation, whether that is an obstacle on or near the aquarium's walls, or a pet or child that blocks normal movement of the mechanism or even touches it.        